Hi,

thanks for the info, I will have a look at the Optex & other units mentioned.

I was planning on fitting switches on the doors & windows, but I would be happier with some form of area coverage as a backup.

I've never had my hands on a dual detector & had no idea they were adjustable.

I was concerned that it would detect people on the path through the fibreglass door, or through the windows, depending on where it was located.

The PIR is adjustable via a hight adjustment screw on the board which alters the coverage patern, and the microwave is seperatly adjustable via a small pot, so you set it to just alarm within the protected area, dont set it too high as it will penetrate well outside the protected area.

But anyhow, both parts of the dualtech have to trigger to set the detector into alarm condition, the pir or microwave on their own is not enough - they must be triggered by both technologies at the same time to alarm.

Hence they cut down false alarms in more hostile environments, as where a pir on its own might cause problems.

Edited March 19, 200521 yr by DNS Security